Why did he like my pic on insta?

So i was dating a guy a long while ago, didn't work out because of timing on his side. I got over it, maybe we'd have a chance later in life. A few months back he told me he was moving from the east coast to the west coast, out of the blue (no contact before this). Me, thinking I was over it, invited him over and we ended up bootycalling for a few weeks before he left. I realised I still had some feelings, told him, and he replied respectfully but basically "that sucks for you, bye". Anyway, half a year later, he likes a pic on insta, which he never does/did, and it made me wonder what his thoughtproces was... Anyone got some insights?
Why did he like my pic on insta?
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